1. Field of the Invention
The invention concerns a process for the delignification and bleaching of cellulosic fibers and more particularly concerns an improvement in the use of chlorine dioxide to bleach cellulose pulps.
2. Brief Description of the Prior Art
The delignification and bleaching of cellulosic pulps employing chlorine dioxide as the active agent is a well known procedure; see for example U.S Pat. Nos. 2,513,788; 3,345,250; 3,619,350; 3,720,577; German Pat. No. 413,338 (1925); and Monograph No. 27, Technical Association for the Pulp and Paper Industry, Chapter 8, (1963).
The use of vanadium containing compounds as catalysts to permit the bleaching of cellulose pulps with alkali metal chlorates and alkaline earth metal chlorates has been described prior to the invention; see for example U.S. Pat. Nos. 2,929,757; 2,938,826 and Rapson et al., TAPPI, 42, No. 8, August 1959, pages 642-649.